On Fri, Dec 20, 2013 at 09:21:54AM +1300, Robert Collins wrote: > The default ephemeral filesystem in Nova is ext3 (for Linux). However > ext3 is IMNSHO a pretty poor choice given ext4's existence. I can > totally accept that other fs's like xfs might be contentious - but is > there any reason not to make ext4 the default? > > I'm not aware of any distro that doesn't have ext4 support - even RHEL > defaults to ext4 in RHEL5. > > The reason I'm raising this is that making a 1TB ext3 ephemeral volume > does (way) over 5GB of writes due to zeroing all the inode tables, but > an ext4 one does less than 1% of the IO - 14m vs 7seconds in my brief > testing. (We were investigating why baremetal deploys were slow :)).
I've no objection to changing the default in this way. I would suggest though that we make the hoice of emphemeral filesystem configurable per-instance. I can well imagine people wanting to be able to choose xfs or btrfs instead of ext4. My suggestion would be to support a glance image metadata property to let users specify the filesystem that is suitable for use with their image. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
